1. Field of the Invention
The present invention is a device designed to locate the spine, or strong side, of a golf club shaft. The device, in its preferred mode, comprises an indicator handle, a support structure, and the usage of a traditional vice means. A golf club shaft is held in place at one end by the vice, and extends through the support structure, which is equipped with roller bearings that function to allow the shaft to rotate on a vertical axis. The distal end of the shaft extends through the indicator handle, which is equipped with roller bearings as well. When tension is placed upon the distal end of the shaft in such a way as to bend the naturally flexing shaft downwardly, the indicator handle allows the user to locate the strongest and weakest points of the shaft. By using this information when affixing the club head onto the shaft in a precise manner, the device will increase the overall performance of the golf club.
2. Description of the Prior Art
Numerous innovations for golf club devices have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present invention as hereinafter contrasted. The following is a summary of those prior art patents most relevant to the invention at hand, as well a description outlining the differences between the present invention and the prior art.
Patent #4,682,504, "Device For Measuring a Stiffness of a Golf Club Shaft," by Kobayashi, represents the closest prior art patent to the present invention. This patent describes a device for measuring a stiffness of a golf-club shaft comprises a clamp for holding one end of a golf-club shaft so that the golf-club shaft extends in a substantially horizontal position. A pointer member having a tip end and a root portion is detachably attached at the root portion thereof to the other end of the golf-club shaft held by the clamp so that the pointer member extends in a substantially horizontal position perpendicular to a longitudinal axis of the golf-club shaft. A counterweight is detachably attached to the tip end of the pointer member and applies a predetermined flexure and torsion load to the golf-club shaft through the pointer member. A vertical displacement measuring instrument is provided to measure the amount of vertical displacement of the tip end of the pointer member produced by torsion and flexure of the golf-club shaft when the predetermined load of the counterweight is applied to the golf-club shaft through the pointer member.
This prior art patent, however, differs from the present invention in significant respects. Firstly, the Kobayashi patent teaches the usage of a device that keeps the shaft of a golf club stationary while flexure of the club head end can be measured. This is accomplished by a clamping means, including the usage of bolts, securing the grip end of a golf club shaft in a horizontal position. Thus, unlike the present invention, the shaft can not be rotated about and flexure can not be measured at more than one angle selected.
Moreover, in the Kobayashi patent, flexure is measured by securing the grip end of the shaft in a housing and allowing the club head, already affixed on the shaft, to weigh down the distal end of the golf club when the club is fixed in its horizontal position. A vertical ruler-type piece then allows the user to calculate the curvature of the shaft. This secured-grip-end embodiment also allows the Kobayashi invention to measure the level of torsion of the club, or stress caused when one end of the club is twisted in one direction while the other is held motionless.
The present invention, in contrast, is aimed at production of golf clubs in the most effective manner possible. By using the present invention, unlike that of Kobayashi, one can determine the flexure of the shaft when the shaft is bent at any angle of rotation, prior to the club head being secured thereon. Therefore, the user of the present invention can locate the strongest and weakest points of the shaft and affix the club head to the shaft accordingly.
Finally, the present invention may be produced with either an analog or digital pressure indicator on the indicator handle for accurate reading of the curvature of the spine. In addition, the present invention can be produced to include a handle means removably attachable to the shaft for steady and convenient rotation of the shaft during operation.
Additional patents retrieved in a comprehensive search included. #3,992,933, Electromechanical Moment-Independent Deflection Sensor, #5,429,008, Method and Apparatus for Measuring Figure of Deflection of Golf Club Shaft, #4,558,863, Golf Club Shaft, #5,379,641, Method for Measuring the Deflection in the Shaft of a Golf Club for Controlling the Dynamic Loft Angle of a Club, #4,517,843, Material and Component Testing Machine, and #4,958,834, Golf Club Assembly.